New brain imaging findings suggest that the use of selective serotonin reuptake inhibitor (SSRI) medication by pregnant women and a mother’s depressed mood are linked to changes in neonatal brain development.

Our new research, which appears in the journal Depression & Anxiety, indicates that untreated prenatal depression and prenatal SSRI treatment are associated with differences in specific connectivity hubs in the newborn brain.

Depression and antidepressant drugs taken during pregnancy are very common, and have been associated with risks for both the mother and her baby, often leaving women and their clinicians with difficult choices to make about treatment options.

We wanted to better understand how untreated depression, compared to depression treated with antidepressant drugs during pregnancy, affects the baby’s brain, with the end goal of helping clinicians and mothers struggling with the decision for best treatment for them and for their baby.

Using a technique called resting-state functional magnetic resonance imaging (fMRI), we scanned 53 newborns’ brains while they were naturally sleeping to measure the connectivity between parts of the brain. The connectivity between different brain regions reflects the brain’s functional organization.

The infants were born to mothers who were not depressed while pregnant, mothers who were depressed while pregnant but received no medication, and mothers treated with SSRIs for a minimum of 75 days during the third trimester of pregnancy.

Our study found changes in functional connectivity in newborns of mothers who had been depressed during pregnancy and not treated with an antidepressant, as well as in those treated with an antidepressant.

Infants who were exposed to SSRI medication during pregnancy showed increased connectivity in an area of the brain believed to be associated with early auditory processing and language development.

The infants of mothers who were depressed during pregnancy but received no medication, on the other hand, appeared to have brain connectivity findings that might reflect an increased ability to integrate information in brain regions that regulate emotions. Surprisingly, infants of mothers treated with antidepressant drugs did not show these changes.

Moreover, we showed that levels of brain connectivity in newborns were predictive of infant temperament at six months of age.

It is important to emphasize that this study shows an association between SSRI exposure and changes in brain activity, but it does not show that SSRI exposure causes those changes. In addition to a mother’s mood and treatment with an antidepressant during pregnancy, there are many genetic and environmental factors that also shape early brain development.

Depression during pregnancy may have risks for both the mother and her infant. It is important that all mothers suffering from depression or other mental illnesses during pregnancy seek professional health care.

While the results from this study are important and advance our knowledge of early brain development, at this point we do not believe that these findings should influence the decision to start or stop antidepressant treatment during pregnancy. It is important not to assume causality from this or the previous studies examining prenatal SSRI exposure and developmental risk.

Because both antidepressant exposure and maternal depression are closely intertwined, it is often difficult to distinguish the developmental risk associated with each exposure or whether the risk associated with SSRI use is due to a shared relationship with maternal depression.

Regardless, at its core prenatal SSRI exposure is an issue of how best to manage a mother’s mental health during pregnancy and given the impact across two generations, poor maternal mental health during pregnancy should be seen as a major public health issue.

Untreated depression during pregnancy carries its own risks, such as preterm birth and neurobehavioral problems during infancy and childhood.

The potential risks to the infant and child should be balanced against the risks associated with poorly or untreated depression. Non-treatment is never an option.

While some infants might be at risk from a prenatal SSRI exposure – and we don’t know who that might be and how that works – there are many mothers and their children as well who might very well benefit from such treatment. Our task is to figure out who benefits, who is at risk, and why.

The study, “Hub distribution of the brain functional networks of newborns prenatally exposed to maternal depression and SSRI antidepressants“, was authored by Naama Rotem‐Kohavi, Lynne J. Williams, Angela M. Muller, Hervé Abdi, Naznin Virji‐Babul, Bruce H. Bjornson, Ursula Brain, Janet F. Werker, Ruth E. Grunau, Steven P. Miller, and Tim F. Oberlander.